Checker for open-hearth regenerative furnaces



l.. B. LNDEMuTl-a CHECKER FOR OPEN HEARTHREGENERATIVE FURNACES FiledMarch 29, 1944 '.5'l Sheets-Sheet 2 f f l INVENTOR.

BY ,vm

WITNESSES.

m; ,1946. 1 B. LINDEMUTH CHECKER FOR OPEN HEARTH REGENERTIVE FURNACESFiled March 29. 1944 3 Sheets-Sheet 3 INV ENTOR.

rf/AIL/ /f Patented Aug. 6, 1,946

UNITED STATE TENT OFFICE CHECKER FOR OPEN-HEARTH REGENERA- TIVE FURNACESApplication March 29, 1944, Serial No. 528,524

3 Claims.

The invention relates to checkers for open.

hearth regenerative furnaces, particularly thos used for making steel.

In the operation of an open hearth steel furnace much dirt and dust,including fine oxide particles, is carried by the hot gases to thecheckers, on horizontal portions of which a substantial amount of thedust is deposited. Because of the character of the dust and the heat towhich it is subjected, deposits of it grow in sponge-like fritted formand clog passages through the checker. This makes it necessary to cleanthe checkers from time to time, which is diicult to do except theirtops. To clean the passages through a checker to the limited extent thatthis can be done, it is usually necessary temporarilyl to shut down thefurnace.

As usually constructed, the life of checkers has been approximately thatof the open hearth steel furnace with which they are associated, and thecheckers have been rebuilt when the furnace has been closed down forreconstruction. A recent development in the construction of open hearthfurnaces is the use of basic brick for their roofs which has extendedthe lives of the furnaces three or four times that of those having theusual silica brick roofs. An object of this invention is to provide forsuch furnaces checkers Whose lives will be that of the furnace so thatit will be unnecessary to close the furnace down for the purpose ofrebuilding its checkers.

The invention provides for an open hearth regenerative furnace a checkerconstructed of brick that are so shaped and laid as to form a pluralityof Vertical flues which extend from the top to the bottom of the checkerin such a continuous fashion as to have no horizontal ledges on whichdust can deposit, except the top of the checker which can readily becleaned from time to time without interrupting the operation of thefurnace.

The checker is constructed of brick laid in continuous vertical columnswhich are arranged in parallel planes, the columns lying in each planehaving their adjacent ends spaced from each other. 'I'he ends of columnslying in adjacent planes overlap each other so that a continuousvertical flue is formed between the ends'of a pair of adjacent columnslying in one vertical plane and the sides of two columns lying inadjacent vertical planes.

While the flue-forming columns may be formed of plain brick, they areadvantageously formed of brick having vertical ribs lat their ends, theprefered form of brick having two vertical ribs at each of its ends sothat itis shaped like an I-beam. The horizontal joints of brick formingthe columns in each vertical plane are vertically offsetfrom thehorizontal joints of brick forming the columns in each adjacent plane sothat thermal lateral expansion of the brick will not move the columnsout of alignment and present dustreceiving ledges. preferably eiected byusing half brick or one and one-half brick at the bottoms'of the columns1ying in alternate vertical planes thereof and half bricks at the topsthereof or at the tops of the other columns.

To facilitate the laying of the columns, the horizontal meeting faces ofthe brick are provided with interlocking detents of a suitable form toalign brick vertically and also to restrain vertically adjacent brickagainst movement with relation to each other. However, such detents arepreferably omitted from the brick forming the tops of the columns, suchbrick having smooth tops so that they will not be engaged and moved bythe cleaners or dust removers which from time to time are moved over thetop of the checker.

The invention is illustrated in the accompanying drawings, of Which Fig.1 is a horizontal sectional view of a checker, the plane of view beingindicated by the line I--I, Fig. 2; Fig. 2 a vertical longitudinalsectional View taken on the'line II-II, Fig. l; Fig. 3 a verticaltransverse sectional View taken on the line III-III, Fig. l; and Figs. 4and 5 perspective views of full size and half size brick used in formingthe checker.

The checker is built within end walls l and 2, and sidewalls 3 and li,and has a bottoml 5 and a top E. The length of the checker between itsend walls I and 2, and its width between its side walls 3 and t, as wellas its height, may vary according to the requirements of service. Thetop of end Wall l is provided with a gas or an air inlet l connectingwith a furnace, which on reversal of the furnace becomes an outlet forproducts of combustion, and end wall Z is provided with a gas outlet 8for products of combustion which on reversal of the furnace becomes agas or an air inlet. Extending longitudinally of the checker and restingupon its bottom 5 there is a wall li) which is provided with cross fiuesl l and whose upper portion supports the adjacent ends of arches I2 thatare supported at their other ends by walls 3 and 4. Resting on the topsof these arches there are blocks I3 on whose upper faces flue-formingcolumns rest.

Except for the top and bottom courses of some l columns in the checker,each column is formed of brick l5 of the I-beam shape shown particu-This breaking of the joints is larly in Fig. 4, the brick having a flatmain body of rectangular shape and being provided at both sides of eachend With vertical ribs I1. The tops and bottoms of the brick areprovided with interlocking detents of suitable form which may be atransverse groove I8 on the top and a transverse projection I9 on thebottom of each brick. The top brick of each column having a half brickat its lower end may be the same as the brick i except that the upperface is plain, or it may be a half brick 2!! such as shown in Fig. 5.Brick 20 is the same as the brick I5 except that it is half the heightand its top is plain, or in other words, not provided with a groove.While various size brick I 5 may be used, a suitable full size brick maybe 131/2 inches long, 6 inches high and 2 inches thick throughout itsmain body, its end ribs I'I extending one-half inch from the face of thebrick and each having a face 11/2 inches in Width. When brick of thissize are used they form flues that are e x lOl/2 inches in crosssection. By using brick of this form and thickness the entire volume ofthe brick is electively used for absorbing and giving off heat.

The brick just explained are laid in vertical columns arranged inparallel vertical planes, alternate planes thereof being indicated bythe dot and dash lines 25 and 26 on Figs. 1 and 3. The end ribs Il ofthe brick forming each column in cach vertical plane 25 overlie andcontact with the faces of the like ribs at the ends of the brick formingthe columns in each adjacent vertical plane Thus a continuous anduninterrupted vertical flue 21 is formed between the adjacent ends ofadjacent columns lying in one vertical plane and the sides of twocolumns lying in adjacent vertical planes. As shown in Figs. 2- and 3,

there is a half brick 2li at the bottom of each column lying inalternate vertical planes thereof, and a half brick 2B at the tops ofsuch columns. The other columns are formed of full size brick l5, exceptthat the top brick in each such column may be plain instead of beingprovided with a groove.

To eliminate dust-receiving ledges on the tops of the column supportingarches I2, the blocks I3 that rest upon these arches have bases of thesame width as the arches and have tops the same width as ribs I'I of thecolumn-forming brick.

Between the tops and bases of these blocks their 1 sides are tapered asshown in Fig. 2, the taper being so steep that dust Will not deposit ontheir faces. Also, to prevent dust from depositing upon the top of WallI il between arches I2, triangular-ly shaped blocks 3G are placed uponthe top of this Wall, th'e base of such blocks being of the same Widthas the thickness of Wall Ill. Thus from the top to the bottom of thechecker the dues 2'! are continuous and their walls are free fromhorizontal dust-receiving ledges. Preferably there are no cross iluesconnecting these vertical ilues.

Because of the interlocking `detents IS and IS formed on the horizontalfaces of the brick, the columns may readily be laid with unskilled help,and in the upper courses of the columns these interlocking detentsrestrain the brick against moving longitudinally with relation to eachother when a cleaning tool is moved over the top of the checker forremoving dust deposited on it. As is well known, cleaning tools for thispurpose are usually formed of pipes, each having a laterally extendingperforated head for discharging on the top of the checker compressed airled through the pipe. The cleaning h'ead of the tool rests upon and ismoved over the top of the checker. If the upper faces of the brickforming the tops of the columns were provided with detents, the movementof the cleaning ytool would be liable to engage the detents and move theupper courses of brick. This would throw the iiues out of alignment andpresent dust-forming ledges at places which are not readily accessibleto cleaning.

The columns lying in each vertical plane thereof being spaced at theirends from veach other, thermal expansion of the brick horizontally inthe plane of the columns does not throw the columns out of alignmentbecause each brick is free to expand lengthwise. Expansion of the bricktransversely of the checker is transmitted from one column to anotherthrough the vertical ribs at the end of the brick, but the staggering ofthe joints of the columns lying in alternate vertical planes precludessuch thermal expansion from throwing the columns out of alignment.

According to the provisions of the patent statutes, I have explained theprinciple and operation of my invention, and have illustrated anddescribed what I now consider to represent its best embodiment. However,I desire to have it understood that, Within the scope of the appendedclaims, the invention may be practiced otherwise than specificallyillustrated and described.

I claim:

1. A checker for an open hearth regenerative furnace, comprising flatbrick having lateral ribs at their ends laid in continuous verticalcolumns arranged in parallel vertical planes with said ribs extendingvertically, the columns in each said plane having their adjacent endsspaced from each other and having said end ribs overlying and contactingwith those of the columns lying in each adjacent plane to form aplurality of vertical smooth-Wall ues extending continuously from thetop to the bottom oi the checker, arches below said columns extending atVright angles to said vertical planes thereof, and blocks vresting uponthe tops of said arches and supporting the ribbed ends of said columns,said blocks having bases of the same Width as the tops of said archesand having tops of the same widths assaid ribs and having tapered sidesbetween their bases and column-supporting top.

2. A checker for an open hearth regenerative furnace, comprising brickslaid in continuous vertical columns arranged in parallel verticalplanes, the columns in each said plane having their adjacent ends spacedfrom each other and having at their ends vertical sides that areparallel to said vertical planes, said vertical sides of each columnoverlapping the like sides at the ends of columns in each adjacent planeto formv a, plurality of vertical flues extending continuously from thetop to the bottom of the checker, each column forming said iiues beingfree thermally to expand and contract laterally in the direction of saidvertical plane in which it lies, the horizontal joints of the bricksforming the columns in each said vertical plane being vertically offsetfrom the horizontal joints of the bricks forming the columns in eachadjacent plane, the tops of the columns being smooth and lying in ahorizontal plane, and the horizontal meeting faces of the bricks thatconstitute each column being provided with interlocking detents aligningthe bricks vertically and restraining vertically adjacent bricks againstlateral movements with relation to each other.

3. A checker for an open hearth regenerative furnace, comprising flatbricks having lateral 5 ribs at their ends laid in continuous verticalcolumns arranged in parallel vertical planes with said ribs extending invertical alignment at the ends of each column and h'aving their sidefaces lying in planes parallel to said vertical planes, the columnslying in each said vertical plane having their adjacent ends spaced fromeach other and having said side faces of said ribs overlapping the likefaces of the ribs at the ends of columns in each adjacent plane to forma, plurality of vertical ues extending continuously from the top to,

the bottom of the ch'ecker, each column forming said iiues being freethermally to expand and con-

